Originally Posted by
Mr. 66
I would check the chain line, your setup sounds inboard. I use those cranks and I'm not having any issues but I'm running stock 6 gear.
Yeah, possibly the frame was spread, with the weaker driveside chainstay doing all of the bending(?).
A switch to Shimano 9s chain would give added clearance for sure. I say "Shimano" 9s chain because it does actually grab teeth better than all other 9s chains out there, and which might preclude the chain skating atop or between cogs.
Steelbikeguy mentioned removing superfluous protruding metal from the middle ring. I've done this in the past when I had a clearance problem, and it did cure the issue.
A spacer material and a strip of coarse belt-sander stock can be forced in between the middle ring and the chainstay, Then the cranks can be rotated to act as a machining operation. Keep the "sandpaper" moving slightly or it will load up. Have the grit facing in the right direction, lol. Best to protect the paint with thick tape as well before proceeding.